Conveyor systems have four primary components; a drive, a tail or discharge section, a flexible conveyor belt, and the conveyor belt structure.
The present invention relates to the conveyor belt structure, and more particularly, to a rigid top troughing assembly for a catenary conveyor belt structure.
Conveyor belt structures are used to guide and support conveyor belts as they convey material. Commonly, conveyor structures are mounted overhead or on the floor. Catenary structure has become a generic term representing the type of conveyor belt structure as to be described. This system is comprised of four major components; the stand(s), siderails, return rollers(s), and top troughing assemblies. The stand is a weldment used to rigidly mount the return roller(s) and siderails. The return rollers rotate about their axis and support the return belt. The siderails provide a rigid mounting framework for the top troughing assemblies. The top troughing assembly is a series of three idlers which rotate about their axis, interconnected to one another. The two outer idlers are generally called wing rollers, and the center idler is appropriately referred to as the center roller. The wing rollers have a hook affixed to one end to facilitate attachment to the siderails while the other end is manufactured in such a fashion as to accept a coupling link. The coupling link connects two wing rollers with a single center roller to form a top troughing assembly.
In use, the top troughing assemblies carry the conveyor belt loaded with media between the drive and the discharge point. And although the catenary top troughing assembly has provided an easily installed and relatively inexpensive design to manufacture, industry demands of higher load carrying capacities have pushed this design to the limit.
The catenary top troughing idler is seated into a bracket mounted on the siderail. While this bracket is sufficient to stop the top troughing assembly from sliding along the siderails, it does not rigidly secure the assembly to maintain the axis of the rollers perpendicular to the belt. As the loads increase, the center roller of the top troughing assembly is pushed in the direction of the belt travel, bringing the wing rollers out of perpendicularity with the belt. This top troughing assembly must also maintain a clearance between the edges of the idlers because of the inline nature. Under heavy offset loading of the belt, the clearance between one edge of the center idler and an edge of a wing roller become narrow, conversely the opposite end of the center roller and the other wing roller become wider, inherent with the hinging effect of the coupling link. This results in a reduced troughing area as well as creating a possibility for the conveyor belt to be pulled through the wider gap created between the center and wing roller. The load placed on top of these top troughing assemblies is supported by the bearing journals of shafts. Since they interconnect, the center roller shaft must carry a larger percentage of the load, thus reducing the load carrying capacity of the troughing assembly.